org.apache.commons.collections4.bidimap
Class AbstractBidiMapDecorator<K,V>

java.lang.Object
  extended by org.apache.commons.collections4.map.AbstractIterableMap<K,V>
      extended by org.apache.commons.collections4.map.AbstractMapDecorator<K,V>
          extended by org.apache.commons.collections4.bidimap.AbstractBidiMapDecorator<K,V>
All Implemented Interfaces:
Map<K,V>, BidiMap<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, Put<K,V>
Direct Known Subclasses:
AbstractOrderedBidiMapDecorator, UnmodifiableBidiMap

public abstract class AbstractBidiMapDecorator<K,V>
extends AbstractMapDecorator<K,V>
implements BidiMap<K,V>

Provides a base decorator that enables additional functionality to be added to a BidiMap via decoration.

Methods are forwarded directly to the decorated map.

This implementation does not perform any special processing with the map views. Instead it simply returns the set/collection from the wrapped map. This may be undesirable, for example if you are trying to write a validating implementation it would provide a loophole around the validation. But, you might want that loophole, so this class is kept simple.

Since:
3.0
Version:
$Id: AbstractBidiMapDecorator.java 1477745 2013-04-30 18:08:32Z tn $

Nested Class Summary
 
Nested classes/interfaces inherited from interface java.util.Map
Map.Entry<K,V>
 
Constructor Summary
protected AbstractBidiMapDecorator(BidiMap<K,V> map)
          Constructor that wraps (not copies).
 
Method Summary
protected  BidiMap<K,V> decorated()
          Gets the map being decorated.
 K getKey(Object value)
          Gets the key that is currently mapped to the specified value.
 BidiMap<V,K> inverseBidiMap()
          Gets a view of this map where the keys and values are reversed.
 MapIterator<K,V> mapIterator()
          Obtains a MapIterator over the map.
 K removeValue(Object value)
          Removes the key-value pair that is currently mapped to the specified value (optional operation).
 
Methods inherited from class org.apache.commons.collections4.map.AbstractMapDecorator
clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, toString, values
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.apache.commons.collections4.BidiMap
put
 
Methods inherited from interface java.util.Map
clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, putAll, remove, size, values
 
Methods inherited from interface org.apache.commons.collections4.Put
clear, putAll
 
Methods inherited from interface org.apache.commons.collections4.Get
containsKey, containsValue, entrySet, get, isEmpty, keySet, remove, size, values
 

Constructor Detail

AbstractBidiMapDecorator

protected AbstractBidiMapDecorator(BidiMap<K,V> map)
Constructor that wraps (not copies).

Parameters:
map - the map to decorate, must not be null
Throws:
IllegalArgumentException - if the collection is null
Method Detail

decorated

protected BidiMap<K,V> decorated()
Gets the map being decorated.

Overrides:
decorated in class AbstractMapDecorator<K,V>
Returns:
the decorated map

mapIterator

public MapIterator<K,V> mapIterator()
Description copied from class: AbstractIterableMap
Obtains a MapIterator over the map.

A map iterator is an efficient way of iterating over maps. There is no need to access the entry set or use Map Entry objects.

 IterableMap map = new HashedMap();
 MapIterator it = map.mapIterator();
 while (it.hasNext()) {
   String key = it.next();
   Integer value = it.getValue();
   it.setValue(value + 1);
 }
 

Specified by:
mapIterator in interface IterableGet<K,V>
Overrides:
mapIterator in class AbstractIterableMap<K,V>
Returns:
a map iterator

getKey

public K getKey(Object value)
Description copied from interface: BidiMap
Gets the key that is currently mapped to the specified value.

If the value is not contained in the map, null is returned.

Implementations should seek to make this method perform equally as well as get(Object).

Specified by:
getKey in interface BidiMap<K,V>
Parameters:
value - the value to find the key for
Returns:
the mapped key, or null if not found

removeValue

public K removeValue(Object value)
Description copied from interface: BidiMap
Removes the key-value pair that is currently mapped to the specified value (optional operation).

If the value is not contained in the map, null is returned.

Implementations should seek to make this method perform equally as well as remove(Object).

Specified by:
removeValue in interface BidiMap<K,V>
Parameters:
value - the value to find the key-value pair for
Returns:
the key that was removed, null if nothing removed

inverseBidiMap

public BidiMap<V,K> inverseBidiMap()
Description copied from interface: BidiMap
Gets a view of this map where the keys and values are reversed.

Changes to one map will be visible in the other and vice versa. This enables both directions of the map to be accessed as a Map.

Implementations should seek to avoid creating a new object every time this method is called. See AbstractMap.values() etc. Calling this method on the inverse map should return the original.

Specified by:
inverseBidiMap in interface BidiMap<K,V>
Returns:
an inverted bidirectional map


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